I was pondering an incoming asteroid scenario to determine if the New Horizons Satellite could be diverted to whack into an asteroid which was detected, say, at the orbit of Jupiter. New Horizons is little but pretty fast. Could it divert an asteroid? The answer is: of course, if the target asteroid is small enough or slow enough.

The problem is that we might not have a satellite handy to plow into stuff. The thing about asteroid busters is that you want them far away from earth and ready to go. You don't want to scramble and launch them from earth when you detect the asteroid. If we were going to set up an asteroid defense, we should launch an armada of these things (preferably ones that explode into a cloud of gas before impact) and have them orbit as far out as we might reasonably be able to detect an incoming asteroid. Then when we see an incoming asteroid we could bring to bear one or more of the asteroid whackers while things are still far enough out to be diverted.
-- bungston, Mar 27 2006

Coming soon... http://neo.jpl.nasa.gov/ca/
Don't forget to wear your hard hat. [Ling, Mar 28 2006]

Historical NEO visits less than 5 times the distance to the moon. http://neo.jpl.nasa...t=dist_min&sdir=ASC
[Ling, Mar 28 2006]

Asteroid crash simulator http://janus.astro.umd.edu/astro/impact/
Nifty crater pictures. [bungston, Mar 29 2006]

NEO groups http://neo.jpl.nasa.gov/neo/groups.html
[Ling, Mar 31 2006]

And the further away you modify the trajectory of an asteroid, the smaller the change needs to be to prevent a collision with earth (assuming that's where you live). Nothing can go wrong now, shirley.
-- methinksnot, Mar 27 2006


hmm... the further away you plan to intercept, the more area you need to cover (by the square of distance), so you'd be looking at more than an armada or million....
-- sophocles, Mar 27 2006


They could be very cheap: just tanks of propellant and enough radio stuff to be steerable. They could be launched by railgun to save on propellant or taken up with the shuttle - or built and launched from the moon. Even if the mass were low they could get going very fast once they had been out there a while - New Horizons is right now tearing along at 21 km/second. They could blow the propellant tanks 5 seconds before hitting the asteroid target to produce the gas cloud.
-- bungston, Mar 27 2006


I think that most of the problem asteroids are already wandering around within the orbit of Mars. This idea seems to be visualizing something in a cometary orbit. An asteroid outside the orbit of Jupiter is going to be very hard to see, and, as annotated above, would be in a very large volume of space, requiring a bunch of boosters.

Earth-based and bloody fast would be better, I think.
-- baconbrain, Mar 28 2006


I seem to remember that one asteroid recently passed between the Earth and the Moon. It wasn't detected until it had already passed by...

Edit: Um, make that more than one...gulp!
-- Ling, Mar 28 2006


if you can change the course of an asteroid with a tiny likkle satellite, the asteroid probably isn;t a threat.

I think the problem is spotting the the danger early enough to do something about it.

I think the current best plan is to send a rocket out to intercept any threat when it's a long way off and either increase or decrease the speed, so it over/under shoot our pretty likkle planet.
-- mattt, Mar 29 2006


[Ling] - I do not see that any of those actually cut between the earth and the moon. All near misses are greater than 1 lunar distance. I was surprised to see a rock got within 3.8 lunar distances, today!

Linked see a simulator where you can plug in asteroid size, speed and composition and then see what would happen if it hit. It shows craters produced by comparable events. This March 28 2005 one gets compared to the Tunguska event by this simulator.
-- bungston, Mar 29 2006


[bungston], check my second link: every one on that page came within 0.01 to 0.4 lunar distances. there are more on the second, third... pages.
-- Ling, Mar 29 2006


Right you are. Hush my mouth.
-- bungston, Mar 29 2006


Ling, note that all of the events listed on your second link are classified as Apollo or similar space junk. See the object classification in the right-hand column.
-- RayfordSteele, Mar 31 2006


Bad news, I'm afraid (and you thought you could breath easy, Eh?):
Just because they are called 'Apollo', doesn't mean they are from the space race...see link 4.
Note, also on the second link, that a '*' indicates a potentially hazardous asteroid.
-- Ling, Mar 31 2006



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